维生素E对免疫应激蛋鸡生产能的影响外文翻译.doc

Vitamin E and stress responseStress (stress) refers to the sum of nonspecific response to external or internal very stimuli, caused by stress factors known as stress factors or stressors (stressor). The mobilization of body tissues and organs to deal with, to adapt to the series of responses to stress stimuli showed that general adaptation syndrome (GAS). It is organized as follows: the physiological changes of adrenocorticotropic hormone (ACTH) production and increased release of, anterior pituitary enlargement. adrenal hyperplasia enlargement. due to increased release of corticosterone and adrenal cholesterol secretion decreased. poult reaction are most sensitive to tissue lymph, thymus, bursa of Fabricius and spleen atrophy; adult chicken because of the influence of gonadal steroids, only the bursal atrophy. The white blood cell changes, showed lymphopenia, heterophils increased. Increase the blood concentration of citric acid. The growth retardation, decreased body weight.The modern intensive livestock production, automation, in order to maximize the level of livestock and poultry production, increase economic efficiency, to livestock and poultry as production machine. The production process and technical measures adopted are often contrary to the animals physiological needs. The resulting stress leads to decrease of slow growth, reduced fecundity, productivity and product quality variation, the immunity of livestock and poultry, causing great harm to livestock and poultry production. In the modern industry production, vaccines for the prevention, control and eradication of infectious diseases of livestock play an extremely important role, immunization hand to protect the body against animal pathogens, on the other hand, as a kind of special stress factor resulting in immunological stress, some damage to the body, the damage is not only affect the growth and development and the production performance of livestock and poultry, and may cause a few animal death.1,the stress response mechanismThe mechanism of stress response is a complex process, according to the Canadian pathologist Hans Selye stress theory, from the stress state of view, can be divided into three periods: alert period (emergency reaction stage), resistance (resistancestage) and failure stage (exhaustion stage). The alert period. The body has not yet received the adaptation period, the body is early response to stressors. According to the physiological and biochemical changes of different, this period can be divided into shock and reverse shock phase. Shock phase as temperature and a decrease in blood pressure, blood concentration, inhibit the nervous system, muscle tension decreased, and then to tissue degradation, hypochloremia, hyperkalemia, gastrointestinal ulceration, body resistance is lower than the normal level. Shock is sustainable for a few minutes to 24 hours. The stress response to enter the shock phase, the defense has been strengthened, increased blood pressure, serum sodium and serum chloride increased, blood potassium reduced, blood glucose increased, catabolism strengthen, atrophy of thymus, spleen and lymph system, eosinophilic leukocytes and lymphocytes decreased, adrenal hypertrophy, improve the total resistance, even higher than that of normal level. In the period of resistance. The body to overcome the stress source and get fit, many performance and panic reaction on the contrary, the new supersedes the old. To be normal, assimilation dominant, white blood cells and adrenal cortex hormone content tended to be normal, systemic non-specific resistance increased to higher than normal level. The failure stage. Performance is like alert period, but the reaction degree increased dramatically, appear all sorts of malnutrition, adrenal cortex although hypertrophy, but cannot produce the necessary hormone, dissimilation again dominated, rapid weight loss, then the reserve depletion, the new supersedes the old. The emergence of irreversible change, to adapt to function damage, leading to death.2. The clinical symptoms of stressBecause the source of stress intensity, duration, chicken breed, age and nutritional status, stress the variety of clinical symptoms, basically divided into the following three types.2, 1 sudden death of stress syndromeChicken in the catch, frightened, vaccine reaction or extrusion strong stressor stimulation, not showing any symptoms, sudden death. This is due to strong stimulation, sympathetic - adrenal system activity, caused by shock or circulatory collapse and sudden death.2, 2 acute stress syndromeMainly due to stress caused by long time strong stimulation, common are the following: heat stress syndrome. The temperature is too high, the hot weather, the crowded transportation, water, chicken body heat too much, difficult heat dissipation, the performance difficulty breathing, mouth breathing, heart rate, body temperature, crown beard flushing cyanosis, muscle tremors, foaming at the mouth, chicken prone to acute bronchial pneumonia and death. convulsive stress. Fight, noise, capture, transport, mixing frightened group process, show head feathers ruffled, panic, tension, hide, loss of appetite, and even waste vast, gain weight, laying rate drop, a few chicken death. cannibalism. Rearing density (crowding stress), the high temperature (heat stress), the light is too strong (light stress), skin trauma and hemorrhage (stress), scabies or other external parasites (such as itching stress) stress stimulation, can cause stress reaction of pecking; protein, vitamin, mineral deficiency nutritional deficiency of cannibalism is a stress response. The clinical manifestations of feather pecking, pecking anal, peck peck, peck toe, meat eggs. you disease. Chicken every day within 2h after the onset of disease, call you. You are chicken to the nest on time, so when the dim and dark house, chicken on a particularly intense, sharp heap, trampling each other, extrusion stress lethal. The muscular stomach injury. Muscle of gastric mucosa erosion or ulcer of the occurrence of chicken.2, 3 chronic stress syndromeBy the stress intensity of the long-term repeated stimulation. For example, the lack of nutrition, competition among individuals, raising no rules, and hunger and satiety, Sherwin sometimes hot and sometimes cold, bacterial, fungal infection, the body continues to make adaptation efforts, forming the cumulative effect of adverse effect of chicken, appetite, causing growth retardation, weight reduction, laying rate drop, the hatching rate. Weakened immune response and defense capabilities, easy to secondary infection of other diseases.3. Stress damage of chickenNormal chicken has the ability to cope with stress from damage, but this ability is limited. The cumulative effect of stress factor or stress beyond protecting threshold, will change from the physiological process for the pathological process. Endanger mainly have the following aspects.3.1Production performanceStress, protein, carbohydrate, fat and increased catabolism, produce more energy to meet the immediate needs, such as heat, accelerated breathing, heartbeat, and fled, and these nutrients for growth, the original weight, immune function, so the indirect effects of the production performance of chickens, performance poult dysplasia, survival rate is low; poultry and egg laying rate drop, egg quality is low, eggs, small deformation, eggshell thinning, brittle, surface roughness, broken egg rate, hatching egg fertilization rate; poultry growth, body weight decreased, the meat quality is poor, low feed reward.3, 2 produce stress syndromeManifestations of renal cortical hypertrophy, lassitude, rapid heartbeat, high blood pressure, loss of appetite, reduced sexual function, slow growth, the most serious from fear of death.3, 3 immune resistanceChicken in the stress, the increase in the secretion of epinephrine, make blood lymphocytes decreased, at the same time, because of increased protein catabolism, used to produce immunoglobulin raw material is relatively reduced, the vaccine, antibody formation was reduced, low antibody level in the body, can not achieve the desired effect of the immune.3, 4 to induce various diseasesStress not only make chicken lower only specific immunity in chickens, and non - specific resistance is generally reduced, easy to induce a variety of diseases, such as bluecomb disease, chronic respiratory disease, infectious coryza, aspergillosis, bursitis, fowl cholera, ulcerative enteritis.4, immunological stressImmunological stress animal is the animal vaccination appear individual allergic, a handful of animal body temperature, some animal anorexia, metabolism, growth, feeding cycle extension phenomenon. Generalized immune also known as immune challenge in immunology, which inject antigen to stimulate the immune response. In the animal life, there are many factors (including infection, trauma and tumor) can cause immune stress. In the immunity during stress, cytokines especially produced by monocytes and macrophages in the inflammatory cytokines IL-1, IL-6 and TNF- mediated inflammation response system, if have a fever, loss of appetite, also plays a role in nutrient redistribution agent, can be used in the growth and skeletal muscle protein deposition of nutrients for related process to maintain the immune response. The amount of inflammatory cytokines produced in favor of the body against infection, but produces too much will cause varying degrees of damage to the body. Especially the TNF- causes pathological reaction in inflammatory conditions or inflammatory diseases. The study found that can activate the immune system of the material are likely to stimulate the body to produce immunity stress (Kelly, 1998). The immune system has the ability to give priority to the use of nutrients, when the animal immune stress, immune system activation, release of cytokines (CK, CK) regulate metabolism process, affecting the growth of demand and the mode properties and nutritional needs. Research shows that, the change of stress is mainly mediated by CK. Webel (1998) to the pig injection of Escherichia coli lipopolysaccharide increases the secretion of IL-6, TNF- , plasma concentration of TNF- 2 hours increased by 10 times. Klasing (1987) to the chickens infected with Actinobacillus pleuropneumoniae were observed after the concentration of serum IL-1 was significantly higher than that in non stress group. Many studies have confirmed that, the livestock and poultry immune stress reduced feed intake, reduce the feed conversion rate, delay the time to market, reduce protein deposition, carcass lean meat rate, eye muscle area reduction. Continuous enhancement of the productivity of laying hens, immune response ability is reduced gradually, in the actual production, although the contact of pathogenic microorganisms chance reduced by improving the health status of new technologies, adopt measures, but the hen is inevitably accept various stimuli, often in a normal stress a return to a normal cycle, production performance the need to maintain, increase the proportion of deposits, reduce skeletal protein, ultimately affect the performance and immune function mechanism 5, immunological stress on immune system of an5、Mechanisms of the immune stress on animal immune systemMechanisms of the immune stress on animal immune system is generally thought to be mediated by glucocorticoid. Adrenal cortical hormone can cause immune suppression. In addition, in the process of immune stress, neuroendocrine system activity changed obviously, which is one of the important factors lead to the change of the function of the immune system. Fan Shaoguang thinks, adrenal cortical hormone mediated stress has a concentration range, he also put under stress, through the central nervous system, the peripheral T lymphocytes produced a large protein molecules, this view may have inhibitory effects on some immune function, inhibit protein called immune, it is immunological stress caused by immunosuppressive opens up a new domain. The body mainly through the hypothalamic pituitary adrenal axis (HPA) system is involved in the regulation of stress response, glucocorticoid is an end product of HPA axis, with corticosterone, cortisol, mainly by the adrenal cortex zona fasciculata secretion, with a wide range of effects on the immune system. The way to participate in HPA axis regulation of stress response, also need to participate in the pituitary thyroid system. In the immune stress, may be increased due to adrenal cortical hormone and thyroid hormone in the body, make the bodys cellular immune function inhibited. Gao Wenwei (2001) suggests that the immune stress, cellular immunity and humoral immunity of the body was inhibited early, later gradually restore. Immunological stress in the blood after ACTH increased, suggesting that the blood ACTH, corticosterone has obvious inhibitory effect on the cell immunity.In the production process of laying hens, vaccination is epidemic link inevitable, effects on performance is quite significant, is a significant problem for development of intensive, large-scale poultry industry. In recent years, immune vaccination caused the chicken immune stress often report. Vitamin E has extensive biological effects on the body, not only has nutrition, and pharmacological effects. In recent years, the function of vitamin E at home and abroad have done a lot of research, but only limited to the production performance, immune function and heat stress, and improve the effects of immunological stress on the aspects of vitamin E are rarely reported, especially vitamin E immune stress adjustment mechanism, the reports are few, is worth discussing.维生素E与应激反应应激(stress)是指机体对外界或内部的各种非常刺激所产生的非特异性反应的总合，引起应激的因素称为应激因子或应激源(stressor)。机体调动全身组织器官以对付、适应应激因子的刺激所表现的系列反应称全身适应综合症(简称GAS)。其组织生理变化如下：促肾上腺皮质激素 (ACTH)生成量和释放量增加，垂体前叶肿大。肾上腺增生肿大。因皮质酮释放量增加而肾上腺胆固醇分泌减少。幼禽最敏感的反应是组织淋巴、胸腺、法氏囊和脾脏萎缩；成年鸡因受生殖腺类固醇的影响，只有法氏囊萎缩。白细胞发生变化，表现为淋巴细胞减少，异嗜白细胞增加。血液柠檬酸浓度上升。生长受阻，体重下降。现代集约化、自动化畜牧生产，为了最大限度地提高畜禽生产水平，增加经济效益，把畜禽当成“生产机器”。所采用的生产工艺和技术措施往往违背了畜禽的生理需要。由此而引起的应激导致畜禽生长发育缓慢、生产力和繁殖力下降、产品质量变差、免疫力减弱，给畜禽生产造成巨大的危害。在现代养殖业生产中，疫苗对预防、控制和消灭畜禽传染病发挥着极其重要的作用，免疫接种一方面保护了动物机体免受病原的侵害，另一方面也作为一种特殊的应激因子引起免疫应激，对机体产生一定的损害，这种损害不仅影响畜禽的生长发育及生产性能，而且可能造成少数动物的死亡。1、应激反应的发生机制应激反应的发生机制是一个复杂的过程，根据加拿大病理学家Hans Selye的应激学说，从经过应激反应的状态来看，可分为三个时期：警觉期(emergency reaction stage)、抵抗期(resistancestage)和衰竭期(exhaustion stage)。警觉期。机体尚未获得适应期，是机体对应激源的早期反应。根据生理生化变化的不同，该期又可分为休克相和反休克相。休克相表现为体温和血压下降、血液浓缩、神经系统抑制、肌肉紧张度降低，进而发展到组织降解、低血氯、高血钾、胃肠急性溃疡，机体抵抗力低于正常水平。休克相可持续几分种至24小时。应激反应进入反休克相，机体防卫反应得到加强，血压上升，血钠和血氯增加，血钾减少，血糖提高，分解代谢加强，胸腺、脾脏和淋巴系统萎缩，嗜酸性白细胞和淋巴细胞减少，肾上腺皮质肥大，机体总抵抗力提高，甚至可高于正常水平。抵抗期。机体克服了应激源作用而获得了适应，许多表现与惊恐反应相反，新陈代谢趋于正常，同化作用占优势，血液中白细胞和肾上腺皮质激素含量也趋于正常，机体的全身非特异性抵抗力提高到高于正常水平。衰竭期。表现很象警觉期，但反应程度急剧增强，出现各种营养不良，肾上腺皮质虽然肥大，但却不能产生必要的激素，异化作用又重新占主导地位，体重急剧下降，继而机体贮备耗尽，新陈代谢出现不可逆变化，适应机能破坏，导致死亡。2、应激的临床症状由于应激源的强度、持续时间、鸡的品种、年龄及营养状态不同，应激的的临床症状多种多样，基本上归纳为以下三种类型。2、1猝死性应激综合症鸡在捕抓、惊吓、疫苗反应或挤压等强烈的应激源的刺激下，不表现任何症状，突然死亡。此乃由于受到强烈刺激，“交感-肾上腺”系统活动增强，引起休克或循环虚脱而至猝然死亡。2、2急性应激综合症主要是由于受到长时间较强的应激源刺激引起，常见的有下列几种：热应激综合症。鸡舍温度过高，炎热天气运输、拥挤、缺水等，鸡体产热过多，散热困难，故表现呼吸困难，张口喘息，心跳加快，体温升高，冠髯潮红发绀，肌肉震颤，口吐白沫，鸡易发生急性支气管肺炎乃至死亡。致惊应激。争斗、噪音、捕捉、运输、混群等过程中受惊，表现头部羽毛竖起，惊恐不安，紧张、躲藏，食欲不振甚至废绝，增重缓慢，产蛋率下降，少数鸡发生死亡。啄食癖。饲养密度大（拥挤应激)，舍温过高（热应激)，光线过强（光应激)，皮肤创伤和出血（创伤应激)，疥癣或其他外寄生虫寄生（痒应激)等应激源的刺激，可引起应激反应性啄癖；蛋白质、维生素、矿物质等缺乏所致的营养缺乏性啄癖也是一种应激反应。临床表现为啄羽、啄肛、啄趾、啄肉、啄蛋。酉时病。鸡每天天黑后2h内发病，称之为酉时病。酉时是鸡归窝上架的时间，如此时舍内暗淡无光，鸡上架骚动特别剧烈，急剧聚堆，相互践踏、挤压产生应激致死。肌胃损伤。鸡的肌胃粘膜发生糜烂或溃疡。2、3慢性应激综合症多由强度不大的应激源长期反复刺激引起。例如营养缺乏，个体间竞争，饲养无规律，忽饥忽饱，舍温忽冷忽热，细菌、霉菌慢性感染等，机体不断地作出适应性的努力，形成不良的累计效应，影响鸡的食欲，致使生长发育迟缓，增重减少，产蛋率下降，孵化率降低。免疫反应能力和防御能力减弱，容易继发感染其他疾病。3、应激对鸡的危害正常鸡有一定对付应激免遭损害的能力，但这种能力是有限的。应激因子或应激的累加作用超越保护阈限时，就会由生理过程转变为病理过程。主要危害有下列几方面。3、1生产性能降低应激时，蛋白质、碳水化合物、脂肪等分解代谢增强，产生更多的能量以应付立即的需要，如热散发、加速呼吸、加快心跳、奔逃等，而这些营养物质原本用于生长、增重、免疫等功能的，所以间接影响了鸡群的生产性能，表现为幼禽发育不良，成活率降低；蛋禽产蛋率下降，蛋品质低下，蛋形变小，蛋壳变薄、变脆，表面粗糙，破蛋率上升，种蛋受精率下降；肉禽生长受阻，体重下降，肉品